Tri-body variable area fan nozzle and thrust reverser

ABSTRACT

A gas turbine engine system includes a fan ( 14 ), a housing ( 28 ) arranged about the fan, a gas turbine engine core having a compressor ( 16 ) at least partially within the housing, and a fan bypass passage ( 30 ) downstream of the fan for conveying a bypass airflow (D) between the housing and the gas turbine engine core. A nozzle ( 40 ) associated with the fan bypass passage includes a first nozzle section ( 54   a ) that is operative to move in a generally axial direction to influence the bypass airflow, and a second nozzle section that is operative to also move in a generally axial direction between a stowed position and a thrust reverse position that diverts the bypass airflow in a thrust reversing direction. An actuator ( 42 ) selectively moves the first nozzle section and the second nozzle section to influence the bypass airflow and provide thrust reversal.

BACKGROUND OF THE INVENTION

This invention relates to gas turbine engines and, more particularly, toa gas turbine engine having a nozzle that integrates functions of avariable fan nozzle and a thrust reverser.

Gas turbine engines are widely known and used for power generation andvehicle (e.g., aircraft) propulsion. A typical gas turbine engineincludes a compression section, a combustion section, and a turbinesection that utilize a primary airflow into the engine to generate poweror propel the vehicle. The gas turbine engine is typically mountedwithin a housing, such as a nacelle. A bypass airflow flows through apassage between the housing and the engine and exits from the engine atan outlet.

Presently, conventional thrust reversers are used to generate a reversethrust force to slow forward movement of a vehicle, such as an aircraft.One type of conventional thrust reverser utilizes a moveable door stowednear the rear of the nacelle. After touch-down of the aircraft forlanding, the door moves into the bypass airflow passage to deflect thebypass airflow radially outwards into cascades, or vents, that directthe discharge airflow in a forward direction to slow the aircraft.Although effective, this and other conventional thrust reversers serveonly for thrust reversal and, when in the stowed position fornon-landing conditions, do not provide additional functionality. The useof a variable area fan nozzle (VAFN) has been proposed for low pressureratio fan designs to improve the propulsive efficiency of high bypassratio gas turbine engines. Therefore, the problem to be solved isintegrating the VAFN functionality with the thrust reverser to reducecomplexity and weight.

SUMMARY OF THE INVENTION

A gas turbine engine system includes a fan, a housing arranged about thefan, a gas turbine engine core having a compressor within the housing,and a fan bypass passage downstream of the fan for conveying a bypassairflow between the housing and the gas turbine engine core. A nozzleassociated with the fan bypass passage includes a first nozzle sectionthat is operative to move in a generally axial direction to influencethe bypass airflow, and a second nozzle section that is operative toalso move in a generally axial direction between a stowed position and athrust reverse position that diverts the bypass airflow in a thrustreversing direction. An actuator selectively moves the first nozzlesection and the second nozzle section to influence the bypass airflowand provide thrust reversal.

An example method of controlling the gas turbine engine system includesthe steps of selectively moving the first nozzle section between an openposition and a closed position to vary an effective cross-sectional areaof the nozzle to control the bypass airflow and selectively moving thesecond nozzle section between a stowed position and a thrust reverseposition to reverse a direction of the bypass flow and produce a thrustreversal force.

BRIEF DESCRIPTION OF THE DRAWINGS

The various features and advantages of this invention will becomeapparent to those skilled in the art from the following detaileddescription of the currently preferred embodiment. The drawings thataccompany the detailed description can be briefly described as follows.

FIG. 1 illustrates selected portions of an example gas turbine enginesystem having a nozzle for varying an effective exit area or producing athrust reversing force.

FIG. 2 illustrates a schematic view of the nozzle in a closed/stowedposition.

FIG. 3 illustrates a schematic view of the nozzle in an open positionfor increasing the effective exit area.

FIG. 4 illustrates a schematic view of the nozzle in a thrust reverseposition.

FIG. 5 illustrates a perspective view of the nozzle in the thrustreverse position.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT

FIG. 1 illustrates a schematic view of selected portions of an examplegas turbine engine 10 suspended from an engine pylon 12 of an aircraft,as is typical of an aircraft designed for subsonic operation. The gasturbine engine 10 is circumferentially disposed about an enginecenterline, or axial centerline axis A. The gas turbine engine 10includes a fan 14, a low pressure compressor 16 a, a high pressurecompressor 16 b, a combustion section 18, a low pressure turbine 20 a,and a high pressure turbine 20 b. As is well known in the art, aircompressed in the compressors 16 a, 16 b is mixed with fuel that isburned in the combustion section 18 and expanded in the turbines 20 aand 20 b. The turbines 20 a and 20 b are coupled for rotation with,respectively, rotors 22 a and 22 b (e.g., spools) to rotationally drivethe compressors 16 a, 16 b and the fan 14 in response to the expansion.In this example, the rotor 22 a also drives the fan 14 through a geartrain 24.

In the example shown, the gas turbine engine 10 is a high bypassturbofan arrangement. In one example, the bypass ratio is greater than10:1, and the fan 14 diameter is substantially larger than the diameterof the low pressure compressor 16 a. The low pressure turbine 20 a has apressure ratio that is greater than 5:1, in one example. The gear train24 can be any known suitable gear system, such as a planetary gearsystem with orbiting planet gears, planetary system with non-orbitingplanet gears, or other type of gear system. In the disclosed example,the gear train 24 has a constant gear ratio. Given this description, oneof ordinary skill in the art will recognize that the above parametersare only exemplary and that other parameters may be used to meet theparticular needs of an implementation.

An outer housing, nacelle 28, (also commonly referred to as a fannacelle or fan cowl) extends circumferentially about the fan 14. Agenerally annular fan bypass passage 30 extends between the nacelle 28and an inner housing, inner cowl 34, which generally surrounds thecompressors 16 a, 16 b and turbines 20 a, 20 b.

In operation, the fan 14 draws air into the gas turbine engine 10 as acore flow, C, and into the bypass passage 30 as a bypass airflow, D. Inone example, approximately 80 percent of the airflow entering thenacelle 28 becomes bypass airflow D. A rear exhaust 36 discharges thebypass airflow D from the gas turbine engine 10. The core flow C isdischarged from a passage between the inner cowl 34 and a tail cone 38.A significant amount of thrust may be provided by the discharge flow dueto the high bypass ratio.

The example gas turbine engine 10 shown FIG. 1 also includes a nozzle 40(shown schematically) associated with the bypass passage 30. In thisexample, the nozzle 40 is shown near the rear of the nacelle 28,however, in other examples, the nozzle 40 is not an exhaust nozzle butis rather located farther forward but aft of the fan 14. In thisexample, the nozzle 40 is coupled to the nacelle 28.

The nozzle 40 is operatively connected with actuators 42 for movementbetween a plurality of positions to influence the bypass airflow D, suchas to manipulate an air pressure of the bypass airflow D. A controller44 commands the actuators 42 to selectively move the nozzle 40 among theplurality of positions to manipulate the bypass airflow D in a desiredmanner. The controller 44 may be dedicated to controlling the actuators42 and nozzle 40, integrated into an existing engine controller withinthe gas turbine engine 10, or be incorporated with other known aircraftor engine controls. For example, selective movement of the nozzle 40permits the controller 44 to vary the amount and direction of thrustprovided, enhance conditions for aircraft control, enhance conditionsfor operation of the fan 14, or enhance conditions for operation ofother components associated with the bypass passage 30, depending oninput parameters into the controller 44.

In one example, the gas turbine engine 10 is designed to operate withina desired performance envelope under certain predetermined conditions,such as cruise. For example, the fan 14 is designed for a particularflight condition—typically cruise at 0.8 Mach and 35,000 feet. The fan14 is designed at a particular fixed stagger angle for an efficientcruise condition. The nozzle 40 is operated to influence the bypassairflow D such that the angle of attack or incidence on the fan 14 ismaintained close to design incidence at other flight conditions, such aslanding and takeoff, thus enabling a desired engine operation over arange of flight condition with respect to performance and otheroperational parameters such as noise levels. In one example, it isdesirable to operate the fan 14 under a desired pressure ratio range(i.e., the ratio of air pressure forward of the fan 14 to air pressureaft of the fan 14) to avoid fan flutter. To maintain this range, thenozzle 40 is used to influence the bypass airflow D to control the airpressure aft of the fan 14 and thereby control the pressure ratio. Insome examples, the nozzle varies an effective cross-sectional areaassociated with the rear exhaust 36 of the bypass passage 30 byapproximately 20% to influence the bypass airflow D.

FIG. 2 illustrates an example of the nozzle 40 for varying the effectivecross-sectional area and functioning as a thrust reverser to slowmovement of a vehicle such as an aircraft, as will be described below.In this example, the nozzle 40 includes a first nozzle section 54 a anda second nozzle section 54 b that is located forwardly adjacent thefirst nozzle section 54 a. The first nozzle section 54 a is moveablebetween a plurality of positions in a generally axial direction relativeto the centerline axis A, and the second nozzle section 54 b is moveablebetween a stowed position and a thrust reverse position that diverts thebypass airflow D in a thrust reversing direction.

In this example, each actuator 42 includes a control section 56 thatcommunicates with the controller 44, and a telescoping member 58 forselectively moving the first nozzle section 54 a and the second nozzlesection 54 b. In this example, the telescoping member 58 includes afirst telescoping section 60 a, such as a cylindrical shaft, connectedwith the first nozzle section 54 a. A second telescoping section 60 b,such as another cylindrical shaft, is concentrically arranged about thefirst telescoping section 60 a and connected with the second nozzlesection 54 b. Given this description, one of ordinary skill in the artwill recognize other types of actuator arrangements suitable for movingthe first nozzle section 54 a and the second nozzle section 54 b.

The second nozzle section 54 b includes a leading end 62 having a curvedsurface 64 that seals against the nacelle 28 in this example. A radiallyinner portion of the second nozzle section 54 b stows blocker doors 66(one shown) that are pivotally attached to the second nozzle section 54b in a known manner. A drag link 68 is pivotally attached at one end tothe blocker door 66 and pivotally attached at its other end to the innercowl 34 in this example. Optionally, the drag links 68 are slidablyconnected to the blocker doors 66, inner cowl 34, or both to facilitatemovement of the blocker doors 66 between the stowed position and thedeployed, thrust reverse position (FIG. 4).

In operation, the controller 44 selectively commands the actuators 42 tomove the first nozzle section 54 a to influence the bypass airflow D orto move the second nozzle section 54 b to provide thrust reversal. Theactuators 42 can independently move the first nozzle section 54 a andthe second nozzle section 54 b. FIG. 2 illustrates the first nozzlesection 54 a in a closed position and the second nozzle section 54 b inthe stowed position sealed against the nacelle 28. In the closed/stowedposition, the bypass airflow D exits axially through the rear exhaust36, and the nozzle 40 has an effective cross-sectional area thatcorresponds to a distance AR between the nozzle 40 and the inner cowl 34in this example.

Referring to FIG. 3, the actuators 42 extend the first telescopingsection 60 a from the second telescoping section 60 b in response to acommand from the controller 44 to move the nozzle from the closedposition to the open position. In the open position, the first nozzlesection 54 a is spaced apart from the second nozzle section 54 b toprovide an opening 70 there between. In one example, the firsttelescoping section 60 a is moved in a known manner using hydraulic orpneumatic power.

The opening 70 provides an auxiliary passage having a cross-sectionalarea proportional to a distance AR′ between the first nozzle section 54a and the second nozzle section 54 b for the discharge of the bypassairflow D. The auxiliary passage provides an additional passage (i.e.,additional effective cross-sectional flow area) for exit of the bypassairflow D from the bypass passage 30 to thereby alter the bypass airflowD. Thus, the total effective cross-sectional area for discharge of thebypass airflow D in this example is AR+AR′.

The controller 44 selectively actuates the first nozzle section 54 a, asdescribed above, to control the air pressure of the bypass airflow Dwithin the bypass passage 30. For example, closing the first nozzlesection 54 a reduces the effective cross-sectional area, which restrictsthe bypass airflow D and produces a pressure build-up (i.e., an increasein air pressure) within the bypass passage 30. Opening the first nozzlesection 54 a increases the effective cross-sectional area, which permitsmore bypass airflow D and reduces the pressure build-up (i.e., adecrease in air pressure). Likewise, a relatively smaller effectivecross-sectional area results in less thrust due to the discharge of thebypass airflow D and a relatively larger effective cross-sectional arearesults in more thrust from the discharge of the bypass airflow D. Inone example, the controller opens the first nozzle section 54 a duringtake-off for additional thrust. Given this description, one of ordinaryskill in the art will be able to recognize other types of nozzles forinfluencing the bypass airflow D.

Referring to FIGS. 4 and 5, the actuators 42 move the second telescopingsection 60 b axially aft in response to a command from the controller 44to move the second nozzle section 54 b from the stowed position to thethrust reverse position. In the thrust reverse position, the secondnozzle section 54 b is spaced apart from the nacelle 28 to provide anopening 72 there between. In one example, the second telescoping section60 b is moved in a known manner using hydraulic or pneumatic power.

Movement of the second nozzle section 54 b causes the drag links 68 topivot the blocker doors 66 into the bypass passage 30. The blocker doors66 block the bypass airflow D and deflect the bypass airflow D radiallyoutwards and forward relative to the centerline axis A through theopening 72. The movement of the second nozzle section 54 b to the thrustreverse position also exposes the curved surface 64. The curved surface64 deflects the bypass airflow D in a forward direction Z to generate areverse thrust force.

In the disclosed example, the first telescoping section 60 a and thefirst nozzle section 54 a move axially when the second telescopingsection 60 b and the second nozzle section 54 b move to the thrustreverse position. Alternatively, the first telescoping section 60 a andthe first nozzle section 54 a remain stationary relative to the secondtelescoping section 60 b and the second nozzle section 54 b such thatthe first nozzle section 54 a closes (i.e., the first nozzle sectionseals against the second nozzle section 54 b to eliminate the opening70).

Optionally, the nozzle 40 includes one or more cascade sections 74 fordiverting the bypass airflow D that is discharged for thrust reversal ina desired direction. In this example, the cascade section includeslouvers 76, such as airfoil-shaped louvers, that divert the dischargedbypass airflow D in directions away from the pylon 12 and away from theground (the bottom of FIG. 5).

The disclosed example nozzle 40 thereby integrates the function ofinfluencing the bypass airflow D with the thrust reversing function. Thenozzle 40 utilizes a single set or system of actuators 42 to eliminatethe need for separate actuators or sets of actuators for altering thebypass airflow D and deploying the thrust reverser. Using a singleactuator or set of actuators 42 as in the disclosed examples eliminatesat least some of the actuators that would otherwise be used, therebyreducing the weight of the gas turbine engine 10 and increasing the fuelefficiency.

Although a preferred embodiment of this invention has been disclosed, aworker of ordinary skill in this art would recognize that certainmodifications would come within the scope of this invention. For thatreason, the following claims should be studied to determine the truescope and content of this invention.

1. A gas turbine engine system comprising: a fan rotatable about anaxis; a housing arranged about the fan; a gas turbine engine core havinga compressor at least partially within the housing; a fan bypass passagedownstream of the fan for conveying a bypass airflow between the housingand the gas turbine engine core; a nozzle having a first nozzle sectionoperative to move in a generally axial direction relative to the axisbetween a plurality of positions that influence the bypass airflow, anda second nozzle section adjacent the first nozzle section that isoperative to also move in a generally axial direction between a stowedposition and a thrust reverse position that diverts the bypass airflowin a thrust reversing direction; and an actuator including a telescopingmember having a first telescoping section coupled with the first nozzlesection such that the first nozzle section is moveable in unison withthe first telescoping section and a second telescoping section coupledwith the second nozzle section such that the second nozzle section ismoveable in unison with the second telescoping section, wherein thefirst telescoping section is telescopically received within the secondtelescoping section, and wherein the first telescoping section and thesecond telescoping section are moveable independently of each other toselectively independently move the first nozzle section and the secondnozzle section.
 2. The gas turbine engine system as recited in claim 1,wherein the second nozzle section includes at least one blocker doorthat is pivotable between the stowed position and the thrust reverseposition, where the at least one blocker door pivots into the bypasspassage in the thrust reverse position.
 3. The gas turbine engine systemas recited in claim 1, wherein the second nozzle section includes acurved leading end section for diverting the bypass airflow in thethrust reversing direction.
 4. The gas turbine engine system as recitedin claim 1, further comprising at least one cascade section between thesecond nozzle section and the housing, the cascade section havinglouvers for diverting the bypass airflow.
 5. The gas turbine enginesystem as recited in claim 1, wherein the first telescoping section isconcentric with the second telescoping section.
 6. The gas turbineengine system as recited in claim 1, wherein the plurality of positionsincludes a closed position wherein the first nozzle section is sealedagainst the second nozzle section and an open position wherein the firstnozzle section is spaced apart from the second nozzle section.
 7. Thegas turbine engine system as recited in claim 1, wherein the secondnozzle section is sealed against the housing when the second nozzlesection is in the stowed position and the second nozzle section isspaced apart from the housing when the second nozzle section is in thethrust reverse position.
 8. The gas turbine engine system as recited inclaim 1, further comprising a controller operative to command theactuator to move the first nozzle section between the plurality ofpositions in response to an aircraft take-off condition and to commandthe actuator to move the second nozzle section to the thrust reverseposition in response to an aircraft landing condition.
 9. A nozzle foruse in a gas turbine engine, comprising: a first nozzle sectionoperative to move in a generally axial direction relative to an enginecenterline between a plurality of positions that influence a bypassairflow through a fan bypass passage; a second nozzle section adjacentthe first nozzle section that is operative to also move in a generallyaxial direction relative to an engine centerline between a stowedposition and a thrust reverse position that diverts the bypass airflowin a thrust reversing direction; and an actuator including a telescopingmember having a first telescoping section coupled with the first nozzlesection such that the first nozzle section is moveable in unison withthe first telescoping section and a second telescoping section coupledwith the second nozzle section such that the second nozzle section ismoveable in unison with the second telescoping section, wherein thefirst telescoping section is telescopically received within the secondtelescoping section, and wherein the first telescoping section and thesecond telescoping section are moveable independently of each other toselectively independently move the first nozzle section and the secondnozzle section.
 10. A method of controlling a gas turbine engine systemincluding a nozzle having a first nozzle section that is moveable tocontrol a bypass airflow within a bypass passage and a second nozzlesection having a stowed position and a thrust reverse position forslowing a vehicle and, the method comprising: (a) selectivelyindependently moving the first nozzle section in an axial directionbetween an open position and a closed position using a first telescopingsection of an actuator that is coupled with the first nozzle sectionsuch that the first nozzle section moves in unison with the firsttelescoping section to vary an effective cross-sectional area of thenozzle to control the bypass airflow; and (b) selectively independentlymoving the second nozzle section in the axial direction between thestowed position and the thrust reverse position using a secondtelescoping section of the actuator that is coupled with the secondnozzle section such that the second nozzle section moves in unison withthe second telescoping section to reverse a direction of the bypass flowand produce a thrust reversal force, wherein the first telescopingsection is telescopically received within the second telescopingsection.
 11. The method as recited in claim 10, wherein said step (b)includes pivoting at least one blocker door of the second nozzle sectionfrom the stowed position to the thrust reverse position, where the atleast one blocker door pivots into the bypass passage in the thrustreverse position.
 12. The method as recited in claim 10, wherein saidstep (b) includes diverting the bypass airflow in a thrust reversingdirection using a curved leading end section of the second nozzlesection.
 13. The method as recited in claim 10, including moving thefirst telescoping section relative to the second telescoping sectionthat is concentric with the first telescoping section to move the firstnozzle section.
 14. The method as recited in claim 10, wherein said step(a) includes moving the first nozzle section from the closed positionwherein the first nozzle section is sealed against the second nozzlesection to the open position wherein the first nozzle section is spacedapart from the second nozzle section to increase the effectivecross-sectional area.
 15. The method as recited in claim 14, whereinsaid step (a) includes increasing the effective cross-sectional area inresponse to an aircraft take-off condition.
 16. The nozzle as recited inclaim 9, wherein the first telescoping section is directly coupled tothe first nozzle section and the second telescoping section is directlycoupled to the second nozzle section.
 17. The nozzle as recited in claim9, wherein movement of the first nozzle section in an axial direction toan open position provides an opening between an axially trailing end ofthe second nozzle section and an axially leading end of the first nozzlesection.
 18. The nozzle as recited in claim 9, wherein movement of thefirst nozzle section in an axial direction to an open position providesan opening between an axially trailing end of the second nozzle sectionand an axially leading end of the first nozzle section, and movement ofthe second nozzle section in an axial direction to an open positionprovides another opening between a leading end of the second nozzlesection and a nacelle.